In a dental field, particularly in a dental technical field, when making a dental prosthesis such as a restorative substance for a tooth and an artificial tooth, a method to form a shape by using a light hardening material before the light hardening material is hardened and to fix the shape by irradiating a light to harden the shape is widely employed. Here, a device which irradiates a light to harden (polymerize) a light hardening material is a photopolymerization device.
Conventionally, a fluorescent lamp, halogen lamp, xenon lamp, and the like are used as a light source of a photopolymerization device. However, these light sources do not necessarily have long life; thus it is necessary to change the light sources quite frequently. Further, the above light sources irradiate a light with a wide wavelength range, so they include a wavelength outside a wavelength range necessary to harden a light hardening material and use an energy for an unnecessary wavelength range; therefore effective irradiation of light cannot be expected.
On the other hand, however, in a case of irradiating a light by using a halogen lamp or xenon lamp, the light source itself becomes a heat source, and thus hardening (polymerizing) by light and hardening (polymerizing) by a heat can be carried out simultaneously; in this respect, despite the cost for replacement due to life expiration, a halogen lamp and a xenon lamp have been used as an importance light source.
With regard to this, Patent Documents 1 and 2 disclose a photopolymerization device which uses a blue light-emitting diode. According to these patent documents, a wavelength which is capable of hardening (polymerizing) a number of commercially available dental light hardening materials matches a wavelength of a blue light-emitting diode. Accordingly, it is possible to provide a photopolymerization device which hardens a light hardening material with a smaller amount of energy than an amount of energy necessitated by a conventional light source, and which does not require frequent replacement of a light source because of a long-life property of a light-emitting diode.
Further, according to a polymerization device disclosed in Patent Document 2, it is possible to set a condition which is suitable for a hardening property of a light hardening material by further providing a heating device to the polymerization device.